Traditionally, when refrigerant charged refrigeration systems were repaired, the refrigerant charge was simply loosed to the atmosphere as necessary to accomplish the repairs. In recent times, it has become increasingly desirable to capture and reuse the refrigerant charges for a number of reasons; refrigerant pollution of the atmosphere is perceived as environmentally destructive, government regulations now limit the release of fluorocarbon refrigerants to the atmosphere, and the cost of refrigerant materials has increased making the disposal and replacement of the refrigerant charge increasingly costly.
Refrigerant recovery devices of the prior art have compressed and cooled refrigerant from charged systems to a liquid state for storage and reintroduction to the same system after repair has been accomplished or for use in other systems. Many of these prior art recovery systems have employed filtration of the refrigerant during the removal-compression-cooling process to remove contaminants from the used refrigerant. However, in today's political climate of increasing environmental concern, many of these systems fail to purify used refrigerants sufficiently to meet standards of proposed and existing environmental regulations. Purification elements by many of the systems of the prior art become contaminated by refrigerant impurities remaining in the apparatus from previous recovery operations or with lubricants which migrate from the compressor when the apparatus is tilted during transport. Also, under certain conditions of sufficiently high refrigerant pressure and cool ambient temperatures, some of the prior art systems are susceptible to entry of liquid refrigerant into the suction side of the recovery system compressor which may cause damage to the compressor and power components of the recovery system. Further, many of the prior art systems may operate satisfactorily only in a limited range of ambient temperature and cannot effectively remove energy from the compressed refrigerant to assure its complete liquefaction prior to its injection into a storage container when ambient temperatures are high.